The H-zone in the skeletal muscle fibre is due to

the absence of myofibrils in the central portion of A-band

the central gap between myosin filaments in the A-band

the central gap between actin filaments extending through myosin filaments in the A-band

extension of myosin filaments in the central portion of the A-band

Solution

the central gap between actin filaments extending through myosin filaments in the A-band

H-zone in skeletal muscle is the central gap between actin filaments extending through myosin filaments in the A-band. Alternate arrangement of dark and light bands gives the striated appearance to a skeletal muscle. At the centre of A-band, a comparatively less dark zone called H-zone is present. In the centre of H-zone, M-line is present, formed by the threats that connect the myofilaments.